London lightweight Martin Ward made a superb start to his European Championship campaign in Ankara with a 20-6 win over Tomasz Vano of Slovakia.
The 19-year-old will face Russian Ildar Vaganov in the last 16 on Monday and said: "It's going to get tougher but I'm confident I can go all the way."
Charlie Edwards beat Vadzim Kirylenko 19-8 on his major international debut in his light-flyweight opener.
Middleweight Anthony Ogogo was pipped 14-13 by Georgian Jaba Khositashvili.
Commonwealth Games gold medallist Thomas Stalker showed no ill effects from his recent move up in weight as he inflicted three standing counts on Georgian Bakur Gogochuri before the referee stopped their contest in round two.
Welterweight Scott Cardle was beaten 17-10 by reigning champion Balazs Bacskai of Hungary.
In Ireland's only action of the opening day, 2008 world youth champion Ray Moylette scored a second round stoppage over his Israeli opponent Subhi Amara in their light-welterweight bout.